1. Field of the Invention
The present invention relates to a running control system of an automobile which runs the automobile at an optimum velocity and space relative to a forerunning vehicle.
2. Related Background Art
Conventionally, a great many efforts and practices have been made to develop component for cruising automobiles at constant velocities and constant car-to-car spaces to simplify driving operations. For example, Japanese Non-examined Patent Publication No.7-47862 (1995) has disclosed a system which enables an automobile to cruise at a preset velocity or at an optimum car-to-car space without the driver's foot on the accelerator pedal.
Further, Japanese Non-examined Patent Publications No.7-225893 (1995) and No.9-71154 (1997) have disclosed systems which automatically start and stop automobiles, freeing the drivers from frequent operations of the brake pedal and the accelerator pedal while the automobile is running slowly. Furthermore, Japanese Non-examined Patent Publication No.10-166898 (1998) has disclosed a system which has two cruising modes (slow cruising mode and fast cruising mode) and switches between these modes to accomplish fast cruising at a preset car-to-car space and low cruising in heavy traffic conditions.
However, the conventional car-to-car space control systems have been designed to calculate an optimum car-to-car space from the velocities of the current and forerunning automobiles. Therefore, for example when finding a stationary object ahead, the automobile running at a high speed must reduce its velocity much earlier to keep an optimum space from the stationary object.
Further, when finding a stationary automobile ahead, the automobile running in the slow follow-up mode must control running to keep an optimum space from the stationary automobile.
Further, almost all drivers have wanted easier and simpler driving operations in all driving ranges.